The present invention relates to a junction having an internal earth and for joining sections of conduits and particularly, but not exclusively, to such junctions for use in environments where hygiene is important.
FIG. 1 shows an example of a metal junction used for connecting lengths of conduit also of metal. The conduit used with this junction are of circular cross section and are not shown in this figure. The junction 10 has a body 12 having first and second connecting portions 14 and 16 for connecting sections of conduit to the junction 12. In use, a cable 18 is inserted along the conduit sections and through connecting portions 14 and 16. A further cable, being an earth cable, (not shown) is also passed through body 12 and is attached in electrical contact with an earthed connecting means 20 which is formed from a base portion 22 which has a threaded aperture, a washer 24 and a fixing screw 26. Typically a short length of the plastic protective coating which surrounds the earth cable is removed and the cable is wrapped around screw 26 and fixed into position. Once all of the cables are in position lid 28, with sealing gasket 30, is located on body 12 and screws 32 are inserted through unthreaded holes 34 and into threaded holes 36 so as to fix lid 28 to body 12.
This type of junction is not at all compact and being circular in shape takes up a considerable volume when placed next to other objects. For example, if placed in a corner between two connecting walls and a ceiling, significant spaces are left between the junction and the walls. These spaces attract dirt and prove difficult to clean, and therefore in industries where hygiene is of paramount importance such a junction would prove unsuitable for this type of location.
An alternative junction 50 is shown in FIG. 2. This junction 50 has a body 52 having connection portions 54 and 56. The junction 50 also has a lid 68 which is attached to body 52 by screws 72 passing through unthreaded holes 74 and into threaded holes 76. This form of junction is preferred in some industries due to its more compact dimensions. Specifically the junction is typically around twice as thick and tall as the diameter of the cross section of the conduit it joins. However, it maintains a large internal volume by having a greater length than the junction 10 of FIG. 1. However, it is not possible to provide the junction 50, used in the junction of FIG. 2, with an internal earthing connection, such as that shown in FIG. 1, since this would obstruct the cables in body 52 and may prevent them from passing through junction 50 as they are fed through the adjoining conduit sections. As a result, external earthing systems are used where an earthed wire extends externally along the path of the conduit sections and is occasionally clamped using external clamping means to the outside of the conduit sections.
In many industries such an arrangement is satisfactory, if somewhat unattractive. However, as previously mentioned, in some industries hygiene is of importance. For example, in the food, beverage or pharmaceutical industries it can be important that the external surfaces of any conduit system are easy to clean. These conduit systems can be made from stainless steel and as many surfaces as possible are smooth and easy to clean. As a result, an externally clamped earthed wire would be unsuitable as this would create a significant number of dirt traps and prove difficult to clean.
The present invention seek to overcome disadvantages of prior junctions.